Medical measuring system

ABSTRACT

In a medical meassuremnet system, measurements can be carried out at a distance from a hospital. Thus the patient is connected to a measuring system comprising measuring sensors and a unit for collecting data comprising a transmitter. The system also comprises a centrally located surveillance unit. The measuring sensors sense various physical and physiological parameters, for example brain activities, actions of the heart, respiration, blood pressure, blood values/tests and body movements. The sensed signals are transmitted to a portable small device of low weight for collecting and/or analyzing data, which is connected to a central surveillance unit, for example via the public switched telephone network (PSTN), a radio system, in particular a cellular radio system, or via a satellite communication. In a preferred embodiment the measuring sensors comprise a preamplifier having an identification circuit. The identification circuit is used for providing each preamplifier with a unique identity. In yet another preferred embodiment a measuring pad for measuring physical and physiological parameters is provided. The measuring pad comprises a film having piezo and/or pyro electrical characteristics, for example a PVF-film (Poly Vinyl Fluoride), or any other sensor having similar properties. By using such a film, which can convert movements into an electrical signal several advantages are achieved.

TECHNICAL FIELD

The present invention relates to a medical measuring system and inparticular to a method and a system for portable measurement,surveillance, transmission recording and analysis of physical,physiological and other functions and parameters.

BACKGROUND OF THE INVENTION AND PRIOR ART

In various medical areas it is sometimes necessary to performmeasurements and surveillance during long periods of time. Examples ofsuch medical areas could be neurology, cardiology, telemedicine,long-term nursing and home nursing. During such long-term measurements,which typically last for days, the patient must at all time be connectedto the measuring equipment in order for a continuous measurement tooccur.

Furthermore, in most cases such measurements must be supervised byqualified personnel in order to prevent interruptions in themeasurements and to check that the condition of the patient does notworsen. The latter is very important since measurements of the kindmentioned above often are included in treatment as follow-upexaminations or in investigations for establishing a diagnosis. Thus, itis common that the person responsible for correctly carrying out themeasurements is a doctor.

These long term measurements must therefore be carried out usingambulatory measurement equipment, since the patient can hardly beexpected to remain in bed during the long periods required for obtaininga continuous series of measurements. Further, the measuring equipmentmust be located at a hospital in order to there be supervised by adoctor in charge.

This is of course expensive for the payer of the hospital care and notparticularly comfortable for the patient who cannot leave the hospitaldespite the fact that he/she is not in any need of hospitalization atthe movement.

SUMMARY

It is an object of the present invention to reduce the costs resultingfrom long-term measurements.

It is another object of the present invention to improve the environmentand reduce the difficulties for patients who need to undergo long-termmeasurements.

It is yet another object of the present invention to provide a measuringpad for measurements of physical and physiological parameters, which isvery sensitive and which therefore can be located at a fairly longdistance from a patient, for example beneath a thick mattress or evenunder a bed.

It is a further object of the present invention to provide apre-amplifier, which is easy to handle and which produces or eliminatesthe risk for erroneous handling, and which is suited to be used togetherwith the measuring equipment.

These objects and others are obtained by means of a method and system bymeans of which the measurements can be carried out at a distance from ahospital. Thus the patient is connected to a measuring system comprisingmeasuring sensors and a unit for collecting data comprising atransmitter. The unit for collecting data preferably also comprisesmeans for performing different analyses. The system also comprises acentrally located surveillance unit.

The measuring sensors sense various physical and physiologicalparameters, for example brain activities, actions of the heart,respiration, blood pressure, blood values/tests and body movements. Thesensed signals are transmitted to a portable small device of low weightfor collecting and/or analysing data, which is connected to a centralsurveillance unit, for example via the public switched telephone network(PSTN), a radio system, in particular a cellular radio system, or via asatellite communication. The central surveillance unit is monitored byqualified personnel which can follow the measurements and also incertain cases reprogram the unit for collecting and analysing dataduring an ongoing measurement.

In a preferred embodiment the measuring sensors comprise a preamplifierhaving an identification circuit. The identification circuit is used forproviding each preamplifier with a unique identity. The fact that eachpreamplifier is given a unique identity makes it possible for the unitcollecting and analysing data to automatically check if the correctpre-amplifier has been attached to the correct input terminal and, ifthat is not the case, either correct the error or give a signalindicating that an erroneous connection has been made.

In yet another preferred embodiment a measuring pad for measuringphysical and physiological parameters is provided. The measuring padcomprises a film having piezo and/or pyro electrical characteristics,for example a PVF-film (Poly Vinyl Fluoride), or any other sensor havingsimilar properties. By using such a film, which can convert movementsinto an electrical signal several advantages are achieved. Thus, ameasuring pad comprising such a film is easy to fold together and can bemade very sensitive, whereby it can be placed beneath the mattress oreven under the bed in which the patient is lying.

Furthermore, the signals transmitted to/from the central surveillanceunit can be image/video signals (if a camera is connected to thesystem), audio signals (such as speech), text signals (for transmissionof prescriptions etc.) as well as biological signals. In this manner thepersonnel at the surveillance end of the system can have full access toinformation required for providing the patient with proper medicaltreatment at distance.

The use of the system as described herein provides a number ofadvantages compared to the prior art. Thus, the patient no longer needsto be in a hospital but can instead be at home or at an another suitablelocation. Hence, by using the system the cost for hospital care isreduced or eliminated. Furthermore the patient can move around freelydue to the fact that the measuring system and auxiliary equipment usedfor collecting data are made small and of low weight.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described more in detail and withreference to the accompanying drawings, in which:

FIG. 1 is a schematic view of an ambulatory medical measuring system.

FIG. 2 is a schematic diagram of a unit for collecting and analysingdata.

FIG. 3 is a schematic diagram of a preamplifier used in the medicalmeasuring system shown in FIG. 1.

FIG. 4 is a section through a measuring pad for use together with themedical measuring system shown in FIG. 1.

DETAILED DESCRIPTION

In FIG. 1 a schematic diagram of an ambulatory medical measuring systemis shown. Thus a unit 1 for collecting and analysing data is connectedto a measuring pad 2 and a preamplifier 3. The measuring pad 2 and thepreamplifiers 3 sense different physical and physiological parametersand are described in more detail below in conjunction with FIG. 3 andFIG. 4. These signals are transmitted to the unit 1 for collecting andanalysing data.

In the unit 1 the signals provided by the measuring pad 2 and thepreamplifiers 3 are AID-converted and stored and analyzed. The digitaldata stored in the unit 1 can then be output from the unit 1 to anexternal computer 4.

The transmission of data to the external computer 4 can be carried outin a number of different ways. In a preferred embodiment thetransmission is carried out using an infrared IR-interface. Such anarrangement has the advantage that the patient can be connected to themeasuring equipment when data is transmitted from the unit 1 to thecomputer 4 without being physically connected to the computer 4. Thus,the risk for electrical current to be transmitted from the computer 4 tothe patient is eliminated.

In another preferred embodiment the unit 1 is also provided with, e.g.,a PCMCIA-card or PC-card or a similar device by means of which the unit1 can connect to a telephone or data network. The computer 4 then doesnot need to be in the same room as the unit 1 when data is transmittedfrom the unit 1 to the computer 4. For example, the unit 1 can belocated together with the patient at home and the computer 4 can belocated at the hospital.

A doctor or another qualified person at the hospital can then connect tothe unit 1 at any time and transmit measurements data from the unit 1via for example the public switched telephone network or a cellularnetwork to the computer 4. In such an arrangement the patient does notneed to be disturbed or even know about when the unit 1 transmits dataand must hence not be bothered by this.

In yet another preferred embodiment the unit 1 can in itself analyze thecollected measurement data. Examples of analyses which the unit 1 canperform are comparisons between measured signals and threshold valuescorresponding to such signals.

Thus, an alarm can be activated in the unit 1 if such a threshold valueis crossed either from above or from below and the computer 4 can beautomatically contacted via the telephone or data network in order forthe doctor or qualified personnel monitoring the computer 4 toimmediately have access to all measurement data, in particular the datacausing the triggering of the alarm.

In this manner an important event in the series of measured data can bespotted quickly, transmitted and possibly taken care of. For example,the information transmitted can form the basis for moving the patient toa hospital in order to perform more thorough investigations and tests orthat an emergency alarm is issued and that actions required areperformed.

Another advantage achieved with such an arrangement is that it ispossible to perform adjustments in the settings at distance. Thus, ifthe doctor or qualified personnel for one reason or another wants tomeasure some another physical or physiological parameter, which atpresent is not being measured, information thereof can be transmittedfrom the computer 4 to the unit 1 and collection of the new desiredparameter can start in the unit 1.

In yet another preferred embodiment data regarding the patients earlierconditions and possible treatment can also be stored and transmittedto/from the unit 1. The unit 1 may also be equipped with aGPS-navigation system for continuous surveillance of the movements ofthe patient and in order to locate the patient quickly in the case analarm signal is transmitted and the patient must be located quickly.

In FIG. 2 a schematic block diagram of the unit 1 is shown. Thus, theunit 1 comprises an input terminal 10 for analogue signals and an inputterminal 12 for digital signals. The analogue input terminal isconnected to a unit 14 wherein the signal is amplified and filtered. Theoutput signal from the unit 14 is fed to an A/D-converter 16 wherein thesignal from the unit 14 is converted into a digital format.

The output signal from the A/D-converter is fed to a computation andcontrol unit 18. The signals input at the terminal 12 are also connectedto the unit 18. The unit 18 is connected to a memory 20 in whichinformation can be stored and from which the unit 18 can readinformation. The unit 18 is also connected to a unit 22 arranged totransmit and receive information from outside the unit 1. The unit 22can for example be a wireless modem or another suitable interface.

The unit 1 can further comprise a power supply unit 24, for example arechargeable or replaceable battery. In a preferred embodiment the powersupply unit comprises a back-up function so that a battery can becharged or replaced without having to interrupt an ongoing measurement.

The unit 1 may also have an input terminal 26 to which equipment forcontrol, calibration or analysis of the unit 1 can be connected.

In FIG. 3, a schematic block diagram of the pre-amplifier 3 is shown.Thus, the pre-amplifier 3 comprises a first amplifier 303, which isconnected to a number of input terminals arranged to receive plug-incontacts for electrodes, which are attached to a person from whommeasured data are collected.

The amplifier 303 is connected to a digital filter 305. The filter 305filters the signals using a suitable filter. The filter may by differentfor different types of signals as described below.

The filter 105 is in turn connected to a second amplifier 307 whereinthe signals are amplified a second time to a suitable output amplitude.The amplifier 307 is connected to an output terminal through which thepre-amplifier 3 can be connected to the unit 1. The pre-amplifier 3 canalso be equipped with a wireless interface towards the unit 1. If suchan arrangement is employed the need for cables and input/outputterminals can be dispensed with.

Furthermore, the pre-amplifier 3 comprises an identification andcalibration unit 309. The unit 109 can communicate with the unit 1 orwith another external unit via a bi-directional data communication line.Thus, the unit 1 can read a unique ID-number and also, in a preferredembodiment, read calibration data stored in the unit 109.

In a preferred embodiment the ID-number and the calibration data can beread continuously or every time the pre-amplifier is connected to theunit 1.

IN another preferred embodiment the pre-amplifier 3 can be informed ofwhich type of signal which is to be measured. This is accomplished bymeans of a special protocol, which informs the pre-amplifier that aparticular type of signals are to be measured, for example heart orbrain signals.

Since the pre-amplifier is informed of which type of signals that are tobe measured the filter 105 can be adjusted for that type of signals andalso the amplifiers 103 and 107 can be set to levels, which are suitablefor the type of signals to be measured.

Since each pre-amplifier 3 is given a unique identity the unit 1 cansense if the correct pre-amplifier has been connected to thecorresponding input terminal of the unit 1. If this is not the case, theunit 1 can correct the mistake or give a signal informing the user ofhis/her mistake.

Furthermore, since the unit 1 and/or the pre-amplifier 3 has knowledgeof which type of signal that is to be measured, an alarm signal can beissued if the wrong type of signal is measured.

In FIG. 4, a section through the measuring pad 2 is shown. The pad 2comprises a pressure sensitive element 201 made of a material such as aPVF-film or another type of film, which generates an electrical voltagein response to physical movements or pressure changes. Around theelement 201 a protective coating 202 is arranged.

The coating 202 isolates the element 201 from static voltages and otherelectrical noise. The pad 2 is preferably further provided with a shockabsorbing material 203, which protects the element 201 from impacts. Thematerial 203 is preferably a rubber material or another suitableflexible and robust material.

The pad 1 has an outer coating made of a water resistant material 204,which prevents liquid from getting into contact with the pressuresensitive element 201. The element 201 can further communicate with theunit I via a cable 205, which is connected to the unit 1 and to theelement 201. The cable 205 is passed through the outer coating 204 ofthe pad 2 through a watertight passage.

In another preferred embodiment the interface between the unit 1 and thepad 2 is wireless. The element 201 then emits signals to the unit 1 viaa wireless modem or via infrared (IR) light, or in any other suitablemanner.

A portable system as described herein can be made of very low weight andthe measuring parts of the system, i.e. the electrodes and itspre-amplifier(s), and the measuring pad, are therefore easy to bringalong when a patient using them wants to move around. This gives thepatient much more freedom than what can be achieved with the prior art.

What is claimed is:
 1. A portable medical measuring system comprising: aplurality of sensors for measuring a plurality of physiologicalparameters of a patient; a data-collecting unit connected to the sensorsfor receiving signals from the sensors; said sensors and data collectionunit being portable and mountable to a patient's body and easily carriedaround by the patient; and a remote surveillance unit located at adistance from the data-collecting unit and communicating over abi-directional communication path with the data-collecting unit, amemory in the data-collecting unit accessible from the remotesurveillance unit, the memory collecting physiological data from thepatient over a long term and storing data regarding a plurality of thephysiological parameters sensed.
 2. A system as recited in claim 1wherein at least one of said sensors measures respiration.
 3. A systemas recited in claim 1 wherein at least one of said sensors measure brainactivities.
 4. A system as recited in claim 1 wherein said surveillanceunit transmits control signals to said data collecting unit forcontrolling said data collecting unit to change the physiologicalparameters being collected by the data collecting unit.
 5. A system asrecited in claim 1 further comprising at least one physical parametersensor, and wherein said data collecting unit collects data regarding atleast one physical parameter from said at least one physical parametersensor.
 6. A system as recited in claim 1 wherein said sensors and datacollecting unit are mounted on the patient, and wherein said systemcontinuously monitors the movements and location of the patient.
 7. Asystem as recited in claim 1 further comprising a signal amplifierdevice interconnected between at least one of said sensors and saiddata-collecting unit, said signal amplifier device having anidentification circuit for automatic identification of said amplifier tosaid data-collecting unit.
 8. A system as recited in claim 7 whereinsaid signal amplifier device is capable of storing calibration data. 9.A system as recited in claim 7 wherein said amplifier device comprises asignal filter, the parameters of which can be controlled in response tocontrol signals from said data collecting unit.
 10. A system as recitedin claim 1 further comprising a pressure sensitive element made of afilm which converts pressure changes into an electrical signal, saidpressure sensitive element operatively connected to said data collectionunit.
 11. A system as recited in claim 10 further comprising a shockabsorbing elastic material disposed around said film of said pressuresensitive element.
 12. A system as recited in claim 11 wherein saidshock absorbing elastic material comprises rubber.
 13. A system asrecited in claim 10 wherein said film comprises polyvinyl fluoride. 14.A system as recited in claim 1 further comprising a measuring pad, saidmeasuring pad comprising a pressure sensitive element, a protectivecoating surrounding said pressure sensitive element and electricallyisolating said pressure sensitive element, and a shock absorbingmaterial encapsulating said protective coating.
 15. A system as recitedin claim 14 wherein said shock absorbing material comprises rubber. 16.A portable medical measuring system comprising: a plurality of sensorsfor measuring a plurality of physical parameters of a patient; adata-collecting unit connected to the sensors for receiving signals fromthe sensors; said sensors and data collection unit being portable andmountable to a patient's body and easily carried around by the patient;and a remote surveillance unit located at a distance from thedata-collecting unit and communicating over a bi-directionalcommunication path with the data-collecting unit, a memory in thedata-collecting unit accessible from the remote surveillance unit, thememory collecting physical data from the patient over a long term andstoring data regarding a plurality of the physical parameters sensed.17. A system as recited in claim 16 wherein said sensors include atleast one sensor for sensing body movements of the patient, said datacollecting unit collecting data relating to body movements of thepatient.
 18. A measuring pad comprising: a pressure sensitive element, aprotective coating surrounding the pressure sensitive element,electrically isolating the pressure sensitive element, and a shockabsorbing material encapsulating the protecting coating.
 19. A pad asrecited in claim 18 wherein the shock absorbing material is a rubbermaterial.
 20. A portable medical data unit comprising: a plurality ofinput terminals for sensors provided for measuring physiologicalparameters of a patient, a communication device for communicating over abi-directional communication path with a remote surveillance unitlocated at a distance from the data-collecting unit; a memory in thedata-collecting unit accessible from the remote surveillance unit, thememory collecting physiological data from the patient over a long termand storing data regarding a multitude of physiological parameters fromsaid input terminals; and said portable medical data collecting unitdimensioned and configured to be mounted to a patient's body and easilycarried around by the patient.
 21. A unit as recited in claim 20 whereinsaid memory collects data relating to respiration.
 22. A unit as recitedin claim 20 wherein said memory collects data relating to brainactivities.
 23. A unit as recited in claim 20 wherein said unit receivescontrol signals from a remote surveillance unit, and changesphysiological parameters being collected in response to said controlsignals.
 24. A unit as recited in claim 20 wherein said memory furthercollects data regarding physical parameters.
 25. A unit as recited inclaim 20 wherein said unit continuously monitors a location of a patienton whom said unit is mounted.